1. Field of the Invention
This invention relates to aromatic fluorophosphorus compounds and their use as antioxidants in organic materials such as organic polymers.
2. Description of the Prior Art
Phosphites, phosphonites and other organic phosphorus compounds are used in organic polymers and other organic materials as antioxidants. They are generally considered better than phenolic antioxidants at high temperatures because these materials eliminate hydroperoxides which decompose and lead to autooxidation chain reactions. Thus, phosphorus compounds are important for oxidative stability during various operations including polyolefin extrusion.
Phenolic and phosphorus antioxidants are often used together in polyolefin homopolymers and copolymers to provide antioxidant protection for both low and high temperature exposure. Unfortunately, additional expense is encountered as additives in larger amounts are needed for the polymers. Thus, there exists a need for effective antioxidants at a reasonable additive price, not only for polyolefins, but other substrates as well.
It is common practice to include an antioxidant in organic materials normally susceptible to oxidative degradation. Many of the antioxidants employed have limited effectiveness or tend to impart undesirable properties to the organic material such as causing color. The problem is particularly acute with polymers and copolymers of ethylenically unsaturated monomers, especially polyolefins such as polypropylene. These materials are subjected to elevated temperatures during processing, which tends to destroy many antioxidants with the result that the polymer rapidly degenerates during use. The aromatic fluorophosphorus compounds of the present invention allow organic materials to maintain excellent color and thermal stability.